Belt-tightener.



H. J. MITCHELL:

BELT TIGHTENER.

APPLICATION FILED OCT. 7. 1915.

1 188,810 PatentedJune 27, 1916.

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H. J. MITCHELL.

BELT TIGHTE NER.

APPLICATION FILED OCT. 7, 1915.

l 1 88,8 1 0. Patented June 27, 1916.

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HARRISON J. MITCHELL, OF BELOIT, WISCONSIN, ASSIGNOR TO 1?. B. YATES MACHINE COMPANY, OF BELOIT, WISCONSIN, A CORPORATION OF WISCONSIN.

BELT-TIGI-ITENER.

Application filed Uctober 7, 1915.

To all whom it may concern:

Be it known that I, HARRISON J. MITCHELL, a citizen of the United States, residing at Beloit, in the county of Rock and State of WVisconsin, have invented certain new and useful Improvements in Belt-Tighteners, of which the following is a specification.

My invention pertains to features of novelty and improvement in belt-tighteners, and similar structures,whereby, upon increase of load on the driven machine, and, consequently, on the belt, the appliance will automatically tighten the latter to enable the belt to more readily and efficiently transmit the required increase of power.

A further aim of the invention is to so construct the device and associate its elements together that upon loosening or rendering the belt-tightener inoperative, the amount of contact of the belt with, or its extent of wrap around, the pulley of the driven machine will be decreased, preventing unintentional driving of the machine.

Another salient feature of the structure is the provision of means for supporting the lower stretch of the belt, preventing undue sagging in its loosened condition. y

Additional objects of the invention are the provision of an appliance of this character which is inexpensive to produce, which is effective in operation, which avoids the use of a heavy weight, and which is composed of few parts likely to become damaged or deranged in service.

From an understanding of the construction and operation of a desirable embodiment of the invention illustrated in the accompanying drawings, and described in detail below, it will be seen that these, with other objects, have been accomplished in such an appliance.

In these drawings which form a part of this specification, like reference characters refer to the same parts throughout the various views.

In these drawings: Figure 1 is a side elevation of the belt-tightener structure in operative condition; Fig. 2illustrates the same appliance with the belt loosened; Fig. 3 is a fragmentary plan view of the apparatus, and Fig. 4c is a sectional detail of the loose connection between two parts of the apparatus.

Referring to such preferred embodiment of the invention illustrated in these drawings, it will be observed that the driving- Specification of Letters Patent.

Patented June 27, 1916.

Serial No. 54,476.

shaft 10 is equipped with a pulley 11 encircling which is a belt or band 12 passing around the pulley 13 of the driven machine 1a, which, for example, may be a planer, matcher, surfaoer, or similar woodworking, or other machineof anywell-known type. In this machine, the standard or frame has an upright-extension 15 equipped with a bearing 16 receiving a shaft 17 on which is fixed an arm 18 revolubly supporting on suitable stud shafts a pair of belt-tightening pulleys 19 and 20 around which the upper length or stretch of the belt passes in a re verse curve or substantially letter 8 form. The non-r0tatable stud-shaft of pulley 20 has an arm 21 fixed thereto carrying a roller or stud 21 positioned beneath such portion of the belt or band. Shaft 17 also has an arm 22 rigid therewith, connected by a link 23 to a bell-crank operating or controlling handle 24. Obviously, the manipulation or swinging of such handle will rock the arm 18 and its pulleys to tighten or loosen the belt, as the case may be.

The protruding end of shaft 17 has a slotted arm or member 25 fixedly mounted thereon, the slot 26 extending beyond the shaft. in opposite directions. Such slot accommodates a roller 27 on the upper end of a link 28, the lower end of which is pivoted to an arm 29 on a shaft 30, revolubly sup ported in any approved manner 011 the machine-frame, which shaft carries one or more longer arms 31 in which another belttightener or controlling pulley 32 is rotatably mounted and positioned beneath the lower length or portion of the belt. Pulleys 19 and 20 may be considered as constituting one belt tightening device, the pulley 32 representing a similar companion or supplemental device or a controlling appliance for the upper belt-tightener.

Operation: The operation of this mechanism is substantially as follows: Y Vhen the handle 24 is up in the position indicated in Fig. 1, the arm 18 is in such position that its two pulleys 19 and 20 tighten or take the slack out of the belt, the roller 21 being inoperative. lVith these parts in the positions indicated, the slot 26 is inclined in the direction shown in Fig. 1, its lower-end receiving the roller 27, which, with the connecting link 28 supports the pulley 82 in slack-removing or tightening engagement with the under surface of the lower stretch of the belt. If the load on the machine becomes augmented the lower length of the belt tends to straighten out and depress pulley 32,

such movement being transmitted through the connecting mechanism to arm 18, which is rocked counter-clockwise, as the parts are viewed in Fig. 1, causing its pair of pulleys to still further tighten the upper stretch of the belt. In fact, such shifting of the pulleys l9 and 20 much more than compensates for the depression of pulley 32 and its loosening effect on the lower length of belt. In this way the driving-power of the belt is enlarged upon increase of load. hen itis desired to render the belt inoperative on pulley 13, the operator rocks handle 2% downwardly, turning the shaft 17 arm 18, pulleys 19 and 20, and slotted arm 25 in a clockwise direction, thus rendering the pulleys inoperative as belt tighteners. Such rocking of member 25 permits roller 27 automatically to travel down the now oppositely-inclined slot, in this way controlling the position of pulley 32, which, under these circumstances, is employed merely to support the lower stretch of the belt and prevent undue sagging. The rocking of arm 18, of course, elevates roller 21, which lifts the upper length of belt away from pulley 13, as shown in Fig. 2, sufficiently clecreasing its contact with the pulley to prevent an operative driving connection be tween the two.

From this illustration and description, it will be perceived that the appliance comprises two belt-tightening devices so connected together that the straightening of a portion of the belt due to increase of load acts upon one of the devices to increase the belt-tightening effect of the other, this con- 'nection between the two devices being such that when the belt is slackened the one of them will operate to support a stretch of the belt without excessive sagging.

, While I have herein set forth with some degree of particularity a desirable embodiment of the invention, it will be understood by those skilled in the art, that many minor mechanical changes may be made in the structure shown and described without departure from the substance ofthe invention and without the sacrifice of any of its substantial benefits and advantages.

I claim: 1. In a belttightening appliance of the character described, the combination of a pair of belt-tightening pulleys engaging a length of the belt cooperating with driving and driven pulleys, a movable support for said pair of pulleys, a third pulley engaging the opposite length of the belt, a movable support for said third pulley, and means connecting said movable supports, whereby upon movement ofthe third pulley by reason of the tightening of its length of the belt under increased load, the pair of pulleys are shifted to take up slack in their length of the belt, substantially as described.

2. I11 a belt-tightening appliance of the character described, the combination of a pair of bolt-tightening pulleys engaging a length of the belt cooperating with driving and driven pulleys, a movable support for said pair of pulleys, a third pulley engaging the opposite length of the belt, a movable support for said third pulley, andmeans connecting said supports, the parts being so constructed and associated that, upon shifting of the third pulley by reason of the tightening of its length of the belt under increased load, said pair of pulleys are shifted to take up more slack in their length of the belt than is removed from the other length of the bolt under its tightening action, substantially as described.

3. In a belt-tightening appliance of the character described, the combination of a pair of belt-tightening pulleys engaging a length of the belt cooperating with driving and driven pulleys, said length of the belt passing around the pair of pulleys in a reverse curve, a movable support for said pair of pulleys, a third pulley engaging the opposite length of the belt, a movable support for said third pulley, and means connecting said supports, whereby upon movement of said third pulley by reason of the tightening of its length ofthe belt under increased load said pair of pulleys are shifted to take up slack in their length of the belt, substantially as described.

4:- In a belt-tightening appliance of the character described, the combination of a pair of belt-tightening pulleys engaging a length of the belt cooperating with driving and driven pulleys, said length of the belt passing around said pulleys in a reverse curve, a pivoted support for said pair of pulleys, a third pulley engaging the opposite length of the belt, aniovable support for said third pulley, and means connecting said supports, whereby, upon movement of said third pulley by the tightening of its length of the belt under increased load, said pair of pulleys are shifted to take up slack in their length of the belt, substantially as described.

5. In a belt-tightening appliance of the character described, the combination of a pair of belt-tightening pulleys engaging a length of the belt cooperating with driving and driven pulleys, a support for said pulleys pivoted between the pulleys, a third pulley engaging the opposite length of the belt, a movable support for'said third pulley, and means connecting said supports, whereby upon movement of saidthird pulley by reason of the tightening of its length of the belt under increased load said first mentioned support and pair of pulleys are rocked to take up slack in their length of the belt, substantially as described.

6. In a belt-tightening appliance of the character described, the combination of a pair of belt-tightening pulleys engaging the upper length of a belt cooperating with driving and driven pulleys, a pivoted support for said pair of pulleys, a third pulley engaging the under face of the lower length of the belt, a pivoted support for said third pulley, and means connecting said pivoted supports, whereby, upon depression of the third pulley by the tightening of its length of the belt under increased load, said pair of pulleys are rocked to take up slack in their length of the belt, substantially as described.

7. In a belt-tightening appliance of the character described, the combination of a pair of belt-tightening pulleys engaging a length of the belt cooperating with driving and driven pulleys, a movable support for said pair of pulleys, means to move said support to bring said pulleys into operative or inoperative position with relation to said length of the belt, a third pulley engaging the opposite length of the belt, a movable support for said third pulley, and means connecting said supports, substantially as described.

8. A belt-tightening appliance constructed' to automatically tighten the belt upon increase of load upon the belt, in combination with means to shift the belt-tightener to inoperative position, and means to decrease the wrap of the belt around the pulley of the driven machine upon such rendering of the belt-tightener inoperative, substantially as described.

9. In an appliance of the character described, the combination of a pair of tightening-devices, means to shift one of said devices into operative or inoperative position, and a loose connection between the de vices, substantially as described.

10. In an appliance of the character described, the combination of a belt-tightening device, and means associated therewith constructed to decrease the wrap of the belt around the pulley of the driven machine when the belt-tightening device is shifted to inoperative position, substantially as described.

11. In an appliance of the character described, the combination of a pair of belttightening pulleys around which the belt takes in a reverse curve, a mounting for said pulleys permitting them to be swung into belttightening or loosening position, and a roller actuated by said mounting cooperating with the belt and adapted to de-- crease the wrap of the belt around the pulley of the driven machine when said belttightening pulleys are shifted to inoperative position, substantially as described.

12. In an appliance of the character described, the combination of a pair of belttightening devices, and means including a loose connection associating said devices together constructed to cause the automatic tightening of the belt upon increase of load on the belt, substantially as described.

13. In' an appliance of the character described, the combination of a rock-arm carrying one or more belt-tightening pulleys adapted to engage a stretch of the belt, a slotted arm movable with said rock-arm, a belt-tightening pulley adapted to engage another stretch of the belt, a pivoted arm on which said latter pulley is mounted, and means connecting said pivoted arm with and adapted to travel in the slot of said slotted arm, substantially as described.

let. In an appliance of the character described, the combination of a rock-arm carrying one or more belt-tightening pulleys adapted to engage the upper stretch of a belt, a slotted arm movable with said rock arm, the slot thereof extending on both sides of the fulcrum of said rock-arm, a belttightening pulley adapted to engage the under side of the lower stretch of the belt, and a mounting for said latter pulley associated with the slot of said arm whereby the weight of the mounting and pulley is imposed on said rock-arm to hold it in operative or inoperative position, substantially as described.

HARRISON J. MITCHELL.

Copies of this patent may be obtained for five cent: each, by addressing the "Commissioner oi Patents.

Washington, D. C." I 

